Chrysanthemum pool pole screening method based on electron back scattering diffraction pattern and medium

Abstract

The invention provides a Kikuchi pole screening method based on an electron back scattering diffraction pattern and a medium. According to a first coordinate and a crystal orientation index of each Kikuchi pole in the electron back scattering diffraction pattern of a to-be-detected sample, a second coordinate of the center of the electron back scattering diffraction pattern, and a distance value between the to-be-detected sample and a screen of a probe, the Kikuchi pole screening method based on the electron back scattering diffraction pattern is obtained; first orientation rotation matrixes corresponding to all Kikuchi pole combinations included in the electron back scattering diffraction pattern are calculated; the second coordinate and the first coordinate are coordinates in the same coordinate system, and the Kikuchi pole combination comprises three Kikuchi poles which are not collinear; performing conversion according to the first orientation rotation matrix to obtain a second orientation rotation matrix, and obtaining a corresponding orientation difference value according to the first orientation rotation matrix and the second orientation rotation matrix, the second orientation rotation matrix being different from the first orientation rotation matrix; and screening a target Kikuchi pole combination according to the orientation difference values corresponding to all Kikuchi pole combinations. According to the invention, the precision of crystal orientation can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of material microstructure characterization and crystal orientation calculation, and in particular to a Kikuchi polar screening method and medium based on electron backscatter diffraction patterns. Background Art

[0002] EBSD (Electron Back-scattered Diffraction) equipment is a complete set of microscopic analysis equipment that can provide statistical crystallographic information of materials over a large range, such as crystal structure, composition, texture, etc.

[0003] EBSD equipment has significant advantages such as simple sample preparation, large analysis area, and strong statistics. Its emergence provides an important and reliable scientific basis for the improvement of material properties.

[0004] The most important raw data obtained by EBSD technology is the crystal orientation, and the accuracy of the crystal orientation depends on the reliability of the selected Kikuchi pole. How to select a reliable Kikuchi pole to calculate the crystal orientation is a problem to be solved. Summary of the invention

[0005] The embodiments of the present application provide a method and medium for screening Kikuchi poles based on electron backscatter diffraction patterns, and select reliable Kikuchi pole combinations to improve the accuracy of the obtained crystal orientation.

[0006] In a first aspect, the present application provides a method for screening kikuchi poles based on electron backscatter diffraction patterns, comprising:

[0007] According to the first coordinate and crystal direction index of each kikuchi pole in the electron backscatter diffraction pattern of the sample to be tested, as well as the second coordinate of the center of the electron backscatter diffraction pattern and the distance value between the sample to be tested and the screen of the probe, the first orientation rotation matrix corresponding to each kikuchi pole combination included in the electron backscatter diffraction pattern is calculated; the second coordinate and the first coordinate are coordinates in the same coordinate system, and the kikuchi pole combination includes three kikuchi poles that are not collinear;

[0008] Converting the first orientation rotation matrix to obtain a second orientation rotation matrix, and obtaining corresponding orientation difference values ​​according to the first orientation rotation matrix and the second orientation rotation matrix, wherein the second orientation rotation matrix is ​​different from the first orientation rotation matrix;

[0009] The target Kikuchi pole combination is screened according to the orientation difference values ​​corresponding to all the Kikuchi pole combinations.

[0010] In some embodiments, obtaining the first coordinate and crystal direction index of the chrysanthemum pole comprises:

[0011] According to the electron backscatter diffraction pattern, all the kikuchi poles are identified and numbered respectively;

[0012] The first coordinate of the Kikuchi pole in a preset coordinate system is obtained, and the crystal direction index of the Kikuchi pole in the crystal coordinate system corresponding to the sample to be tested is obtained. The preset coordinate system is established with any point in the plane where the electron backscatter diffraction pattern is located as the origin.

[0013] In some embodiments, the first orientation rotation matrix corresponding to each Juchi pole combination included in the electron backscatter diffraction pattern is calculated according to the first coordinate and crystal direction index of each Juchi pole in the electron backscatter diffraction pattern of the sample to be tested, the second coordinate of the center of the electron backscatter diffraction pattern, and the distance value between the sample to be tested and the screen of the probe; the second coordinate and the first coordinate are coordinates in the same coordinate system, and the Juchi pole combination includes three non-collinear Juchi poles including:

[0014] Calculate the target matrix corresponding to each of the Juchi pole combinations according to the distance value, the second coordinate, and the first coordinate and the crystal direction index corresponding to each of the Juchi poles in all the Juchi pole combinations;

[0015] According to the preset rotation matrix and the target matrices corresponding to all the Kikuchi pole combinations, the first orientation rotation matrices corresponding to each Kikuchi pole combination are calculated respectively.

[0016] In some embodiments, the formula for calculating the target matrix includes:

[0017]

[0018] Wherein, (x, y) is the first coordinate of the kikuchi pole, (x 0 ,y 0 ) is the second coordinate, [hkl] is the crystal direction index of the kikuchi pole, DD is the distance value, M y is the target matrix;

[0019] The formula for calculating the first orientation rotation matrix includes:

[0020] g=M x ·M y

[0021] Among them, the M x is the preset rotation matrix, and g is the first orientation rotation matrix.

[0022] In some embodiments, converting the first orientation rotation matrix to obtain a second orientation rotation matrix includes:

[0023] The first orientation rotation matrix is ​​transformed according to a preset transformation mode to obtain a corresponding target matrix, wherein the number of elements included in the target matrix is ​​less than the number of elements included in the first orientation rotation matrix;

[0024] The target matrix is ​​transformed according to the preset transformation method to obtain the second orientation rotation matrix; the second orientation rotation matrix has the same number of rows and columns as the first orientation rotation matrix.

[0025] In some embodiments, the preset conversion method includes any one of the mutual conversion between Miller index and rotation matrix, the mutual conversion between Euler angle and rotation matrix, the mutual conversion between angle axis pair and rotation matrix, and the mutual conversion between four elements and rotation matrix.

[0026] In some embodiments, the formula for calculating the orientation difference value includes:

[0027] C=|u-u'|+|v-v'|+|w-w'|+|r-r'|+|s-s'|+|t-t'|+|h-h'|+|k-k'|+|l-l'|

[0028] Wherein, C is the orientation difference value,

[0029] →

[0030] is the first orientation rotation matrix, is the second orientation rotation matrix.

[0031] In some embodiments, screening a target Juchi pole combination according to the orientation difference values ​​corresponding to all the Juchi pole combinations comprises:

[0032] Obtaining a target threshold value according to the orientation difference values ​​corresponding to all the kikuchi pole combinations;

[0033] The target Kikuchi pole combination that reaches the target threshold is screened out from all the Kikuchi pole combinations.

[0034] In some embodiments, obtaining a target threshold value according to the orientation difference values ​​corresponding to all the combinations of the chrysanthemum poles comprises:

[0035] n orientation difference values ​​are selected from all the orientation difference values ​​according to their numerical values; the maximum value of the n orientation difference values ​​is less than any of the remaining orientation difference values, and n≥2 is a positive integer;

[0036] The maximum value among the n orientation difference values ​​is determined as the target threshold.

[0037] In a second aspect, an embodiment of the present application further provides a computer storage medium having a computer program stored thereon, which, when executed by a processor, implements the Kikuchi polar screening method based on electron backscatter diffraction patterns as described in the first aspect.

[0038] The present application provides a method and medium for screening Kikuchi poles based on electron backscatter diffraction patterns. The method flow is to calculate the first orientation rotation matrix corresponding to each Kikuchi pole combination included in the electron backscatter diffraction pattern according to the first coordinate and crystal index of each Kikuchi pole in the electron backscatter diffraction pattern of the sample to be tested, the second coordinate of the center of the electron backscatter diffraction pattern, and the distance value between the sample to be tested and the screen of the probe; the second coordinate and the first coordinate are coordinates in the same coordinate system, and the Kikuchi pole combination includes three non-collinear Kikuchi poles; the second orientation rotation matrix is ​​converted according to the first orientation rotation matrix to obtain the second orientation rotation matrix, and the corresponding orientation difference value is obtained according to the first orientation rotation matrix and the second orientation rotation matrix, and the second orientation rotation matrix is ​​different from the first orientation rotation matrix; the target Kikuchi pole combination is screened according to the orientation difference value corresponding to all Kikuchi pole combinations. The present application performs orientation calculation on all "Kikuchi pole combinations" to obtain the corresponding first orientation rotation matrix and difference value calculation to obtain the corresponding orientation difference value. The larger the orientation difference value, the lower the accuracy of the orientation result (i.e., the first orientation rotation matrix or the Euler angle corresponding to the first orientation rotation matrix) is considered. By comparing the orientation difference values, the present application can evaluate the accuracy of the orientation results calculated by each kikuchi pole when the theoretical orientation value is unknown. By screening the orientation difference values, the present application can screen all the kikuchi pole combinations appearing in a diffraction pattern, and almost all unreliable kikuchi pole combinations can be excluded, completely avoiding the orientation calculation results with large errors, and greatly improving the orientation calculation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 Some exemplary schematic flow diagrams of the Kikuchi polar screening method based on electron backscatter diffraction patterns are shown;

[0041] Figure 2 Schematic diagram showing some exemplary cubic stainless steel electron backscatter diffraction patterns;

[0042] Figure 3Schematic diagram showing some exemplary methods of numbering the kikuchi poles of the stainless steel electron backscatter diffraction pattern and calibrating the crystal direction index and the first coordinate of the kikuchi poles

[0043] Figure 4 A schematic diagram showing the relationship between the orientation difference angle and orientation difference value of some exemplary Kikuchi pole combinations is shown. DETAILED DESCRIPTION

[0044] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of this application.

[0045] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0046] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "exemplarily" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present application. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0047] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0048] When describing some embodiments, the expressions "coupled" and "connected" and their derivatives may be used. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components are in direct physical or electrical contact with each other. For another example, when describing some embodiments, the term "coupled" may be used to indicate that two or more components are in direct physical or electrical contact. However, the term "coupled" may also refer to two or more components that are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents of this document.

[0049] “At least one of A, B, and C” has the same meaning as “at least one of A, B, or C” and both include the following combinations of A, B, and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B, and C.

[0050] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0051] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0052] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of variation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0053] The misorientation angle refers to the angle of orientation difference between two crystals or grains. In materials science, especially in the application of electron backscatter diffraction technology, the misorientation angle is used to describe the orientation difference between adjacent grains or grain boundaries.

[0054] The electron backscatter diffraction pattern includes Kikuchi bands and Kikuchi lines.

[0055] Kikuchi lines are pairs of bright and dark parallel lines that appear in electron diffraction patterns and reflect the orientation and deviation of the crystal.

[0056] Kikuchi line pairs refer to the situation where Kikuchi lines in the same crystal band appear in pairs, that is, each pair of Kikuchi lines corresponds to a crystal plane.

[0057] In the case of symmetrical incidence, that is, when the diffraction crystal plane is parallel to the incident beam direction, dark or bright bands often appear, which are called Kikuchi bands. Different Kikuchi bands correspond to crystal planes with different indices, and the intersection of the Kikuchi bands, i.e., the Kikuchi pole, corresponds to the crystal zone axis of the crystal.

[0058] Kikuchi pole is an important feature in electron backscatter diffraction pattern, which refers to the point where the crystal plane traces of several Kikuchi line pairs intersect, that is, the intersection of the crystal zone axis to which these related crystal planes belong. Kikuchi pole represents the direction of the crystal zone axis in the diffraction pattern, which is determined by the intersection of Kikuchi bands. Kikuchi bands correspond to crystal plane families, so Kikuchi pole is equivalent to the common direction of each crystal plane family corresponding to each intersecting Kikuchi band. In practical applications, the identification of Kikuchi pole is crucial for the identification of crystal structure and symmetry analysis. For example, when using Kikuchi diffraction pattern for crystal structure identification, the type of symmetry axis of the crystal can be determined by identifying Kikuchi pole and its geometric characteristics.

[0059] The Kikuchi line screening system based on electron backscatter diffraction patterns includes EBSD equipment, a scanning electron microscope, a scanning electron microscope, an electron beam control device and a host computer. The electron backscatter diffractometer includes a probe and a data analysis device. The probe is composed of a fluorescent screen (such as a phosphor screen) on the outer surface and a high-sensitivity CCD (Charge Coupled Device) camera behind the screen. The fluorescent screen is mainly used to detect Kikuchi lines, and the CCD camera is mainly used to record Kikuchi lines. The data analysis device is mainly used to analyze the collected Kikuchi lines to obtain various information such as crystal orientation, orientation difference, orientation relationship, crystal structure, etc.

[0060] The EBSD device is installed in a scanning electron microscope, and it is excited by the electron beam of the scanning electron microscope. When the electron beam interacts with the sample to be tested (tilted at a certain angle), some of the electrons with less energy loss will undergo Bragg diffraction with the crystal plane on the surface of the sample to be tested, thereby forming two conical diffraction beams, which are approximately parallel to the crystal plane where Bragg diffraction occurs. The two conical diffraction beams intersect with the fluorescent screen placed in front of the sample to be tested to form an electron backscattered diffraction pattern. The screen of the EBSD device is a fluorescent screen, which is used to receive the backscattered electron signal generated by the sample under the irradiation of the electron beam and convert it into a visible light image including the electron backscattered diffraction pattern. These images can be observed directly on the fluorescent screen, or they can be magnified and stored by a CCD camera and then viewed on the fluorescent screen.

[0061] Crystal orientation is defined as the relative position of the three crystal axes (e.g., crystal axes

[100] ,

[010] ,

[001] ) of the crystal in the sample coordinate system (e.g., RD ​​rolling direction, TD transverse direction, ND normal direction). From a "static" perspective, orientation is the angle between the axes of the crystal coordinate system and the sample coordinate system. From a "dynamic" perspective, crystal orientation represents a rotation operation or coordinate transformation, through which the sample coordinate system can be made to coincide with the crystal coordinate system.

[0062] To calculate the crystal orientation of a single crystal based on the Kikuchi diffraction pattern, at least three Kikuchi poles need to be calibrated in the pattern. The crystal orientation can be calculated by the coordinates and crystal direction indexes of the three non-collinear Kikuchi poles. In a perfect case, choosing any three different Kikuchi poles in a diffraction pattern to calculate the orientation should give consistent results. However, due to inevitable positioning errors and pattern distortion, choosing different Kikuchi poles will give slightly different orientation results. It is difficult to accurately judge the accuracy of Kikuchi pole positioning by naked eye observation or image analysis, and it is difficult to select Kikuchi poles suitable for crystal orientation calculation. In addition to being affected by the absolute position accuracy of the Kikuchi poles, the crystal orientation calculation results are also affected by the relative positions between the three Kikuchi poles. If the relative positions between the Kikuchi poles are accurate but the absolute positions of each are inaccurate, there will not be a large error in calculating the angle between the crystal planes (crystal directions), but it will have a great impact on the crystal orientation calculation. Therefore, the crystal orientation calculation has high requirements for the positioning accuracy of the Kikuchi poles, and a small positioning error will also cause a large crystal orientation calculation error. Selecting a reliable Kikuchi pole to calculate the orientation is particularly important for obtaining high-precision orientation results. Therefore, without knowing the theoretical orientation, how to evaluate the calculation accuracy of the crystal orientation and how to select a more reliable Kikuchi pole to obtain high-precision orientation results are technical problems that need to be solved urgently.

[0063] This application proposes a Kikuchi polar screening method based on electron backscatter diffraction patterns. Figure 1 Schematic diagrams of some exemplary Kikuchi screening methods based on electron backscatter diffraction patterns are shown. Figure 1 The process shown includes the following steps:

[0064] S100. Calculate the first orientation rotation matrix corresponding to each Kikuchi pole combination included in the electron backscatter diffraction pattern according to the first coordinate and crystal direction index of each Kikuchi pole in the electron backscatter diffraction pattern of the sample to be tested, the second coordinate of the center of the electron backscatter diffraction pattern, and the distance value between the sample to be tested and the screen of the probe; the second coordinate and the first coordinate are coordinates in the same coordinate system, and the Kikuchi pole combination includes three Kikuchi poles that are not collinear.

[0065] In some examples, the sample to be tested includes a sample prepared from any one or more of ceramics, metals, semiconductors, minerals, single crystals and polycrystalline materials. The electron backscatter diffraction pattern (hereinafter referred to as the diffraction pattern for ease of description) includes a coaxial transmission mode, an off-axis transmission mode or a normal scanning mode electron backscatter diffraction pattern. The diffraction pattern includes a number of Kikuchi lines, a number of Kikuchi line pairs and a number of Kikuchi bands. The electron backscatter diffraction pattern center (pattern center, PC) refers to the intersection or center position of the diffraction Kikuchi lines in the diffraction pattern.

[0066] A diffraction pattern of a sample to be tested is Figure 2 As shown, the diffraction pattern of the sample to be tested can be collected by the probe of the electron backscatter diffractometer, and then these diffraction patterns are calibrated. During the calibration process, the kikuchi poles in the diffraction pattern are identified and numbered, and the position of the kikuchi pole corresponding to each number is determined. Then, by calculating the crystal plane angle and comparing it with the theoretical value, the corresponding crystal direction index can be obtained. In addition to obtaining the first coordinates and crystal direction index of each kikuchi pole in the electron backscatter diffraction pattern of the sample to be tested, the present application also needs to obtain the second coordinates of the center of the electron backscatter diffraction pattern, the second coordinate and the first coordinate are coordinates in the same coordinate system, and obtain the distance value between the sample to be tested and the screen of the probe.

[0067] The Kikuchi pole is the intersection of the midlines of the Kikuchi line pairs of the same crystal band, forming a symmetry center, which is the intersection of the crystal band axis and the fluorescent screen. When the Kikuchi pole coincides with the diffraction pattern center, it indicates that the direction of the incident electron beam is strictly parallel to the crystal band axis. Each diffraction pattern has a pattern center. This application can directly read the pattern center from the EBSD device, and then obtain the second coordinate based on the position of the pattern center in the preset coordinate system. The second coordinate can be expressed as (x 0 ,y 0 ).

[0068] The EBSD device uses an electron beam to irradiate the sample surface and obtains the crystal orientation information of the sample by detecting backscattered electrons. In this process, the distance between the sample to be tested and the detector (fluorescent screen) is a key parameter because it affects the resolution and measurement accuracy of the diffraction pattern. The distance value from the sample to be tested to the fluorescent screen can be calculated by geometric relationship. For example, the distance value from the sample to be tested to the fluorescent screen can be calculated by z*=(r'-r) / tan(2θ). Among them, z* is the distance value between the sample to be tested and the screen of the probe, r is the distance from one of the two intersection points of the diffraction Kikuchi line to the incident point PC, r' is the distance from the other of the two intersection points of the diffraction Kikuchi line to the incident point PC, θ is the diffraction angle, and tan() is the symbol of the tangent function.

[0069] It should be noted that there is no order in which the first coordinate and crystal index of the Kikuchi pole, the second coordinate of the center of the diffraction pattern, and the distance between the sample to be tested and the screen of the probe are acquired. The acquisition of these data can be performed synchronously or asynchronously.

[0070] In some embodiments, obtaining the first coordinate and crystal direction index of the chrysanthemum pole comprises:

[0071] S110, obtaining an electron backscatter diffraction pattern of the sample to be tested; the electron backscatter diffraction pattern is collected by a probe;

[0072] S120, identifying all the kikuchi poles according to the electron backscatter diffraction pattern and numbering them respectively;

[0073] S130, obtaining the first coordinate of the Kikuchi pole in a preset coordinate system, and obtaining the crystal orientation index of the Kikuchi pole in the crystal coordinate system corresponding to the sample to be tested, wherein the preset coordinate system is established with any point on the plane where the electron backscatter diffraction pattern is located as the origin.

[0074] In some examples, since the positions of the Kikuchi bands and Kikuchi poles in the diffraction pattern are places where the grayscale changes significantly, the grayscale gradient detection method can accurately find these areas where the grayscale changes significantly, thereby achieving the positioning of the Kikuchi bands, center lines and Kikuchi poles. For example, the image of the diffraction pattern is subjected to grayscale transformation and edge detection, and the edge and texture features in the diffraction pattern can be effectively identified by calculating the areas in the image where the grayscale value changes greatly, thereby achieving accurate positioning of the Kikuchi pole. In this way, all the identified Kikuchi poles are numbered respectively, and one Kikuchi pole corresponds to a unique number code, that is, the numbers of all the Kikuchi poles in the diffraction pattern of the same sample to be tested are different.

[0075] The present application uses the plane where the diffraction pattern is located as the reference plane, and sets any point on the plane where the diffraction pattern is located as the origin to establish a two-dimensional preset coordinate system. In this way, the first coordinates of all identified Kikuchi poles in the preset coordinate system, i.e., the Kikuchi polar coordinates, can be expressed as (x, y).

[0076] In addition, the present application can perform Hough transform on the image of the diffraction pattern, quantize the Kikuchi band information in the diffraction pattern into an accumulator, extract the characteristics of the Kikuchi band, compare the Kikuchi band characteristics obtained by Hough transform (for example, the position, width, intensity and angle between the bands) with the theoretical values ​​in the crystallographic library, and calibrate the corresponding crystal plane index by comparing the angle and position of the Kikuchi band. Figure 2 The diffraction pattern shown is numbered and the first coordinate and crystal index are marked as shown in the figure. Figure 3 shown.

[0077] In some embodiments, before obtaining the crystal orientation index, the image of the diffraction pattern may be preprocessed, such as denoising, contrast enhancement, etc., to improve the accuracy of the obtained crystal plane index.

[0078] The present application selects three non-collinear Juchi poles from all the Juchi poles included in the diffraction pattern to obtain a Juchi pole combination (also called a three-Juchi pole group). Similarly, all Juchi poles can be combined to obtain other Juchi pole combinations. In this way, a number of Juchi pole combinations are established for a diffraction pattern, and the three Juchi poles included in each Juchi pole combination are non-collinear. Then, according to the distance value, the second coordinate, and the first coordinate and crystal direction index corresponding to the three Juchi poles in any Juchi pole combination obtained by the above process, the first orientation rotation matrix corresponding to the Juchi pole combination can be calculated. In this way, the first orientation rotation matrix corresponding to all Juchi pole combinations in a diffraction pattern can be calculated.

[0079] In some embodiments, the step S100 calculates the first orientation rotation matrix corresponding to each of the juchi pole combinations included in the electron backscatter diffraction pattern according to the first coordinate and crystal direction index of each juchi pole in the electron backscatter diffraction pattern of the sample to be tested, the second coordinate of the center of the electron backscatter diffraction pattern, and the distance value between the sample to be tested and the screen of the probe; the second coordinate and the first coordinate are coordinates in the same coordinate system, and the juchi pole combination includes three non-collinear juchi poles including:

[0080] S110, calculating and obtaining target matrices corresponding to all the Juchi pole combinations according to the distance value, the second coordinate, and the first coordinate and the crystal direction index corresponding to each of the Juchi poles in all the Juchi pole combinations;

[0081] S120, according to the preset rotation matrix and the target matrices corresponding to all the Kikuchi pole combinations, respectively calculate and obtain the first orientation rotation matrices corresponding to each of the Kikuchi pole combinations.

[0082] In some examples, for the orientation calculation of a single grain, the first coordinates and crystal direction indexes corresponding to three non-collinear kikuchi poles in a kikuchi pole combination are selected in the diffraction pattern, as well as the distance value between the sample to be tested and the screen of the probe, and the second coordinate of the pattern center, and the target matrix corresponding to the kikuchi pole combination can be calculated. In this way, the target matrices corresponding to all kikuchi pole combinations in the diffraction pattern of the sample to be tested can be calculated. The formula for calculating the target matrix includes the following formula (1):

[0083]

[0084] Wherein, (x, y) is the first coordinate of the kikuchi pole, (x 0 ,y 0 ) is the second coordinate, [hkl] is the crystal direction index of the kikuchi pole, DD is the distance value, M y is the target matrix.

[0085] Since the sample to be tested is tilted at a specific angle, coordinate transformation is required, that is, adding the preset rotation matrix M x , the target matrix corresponding to any combination of the kikuchi poles and the preset rotation matrix M x The product calculation is performed to obtain the first orientation rotation matrix corresponding to the kikuchi pole combination, that is, the formula for calculating the corresponding first orientation rotation matrix includes:

[0086] g=M x ·M y (2)

[0087] Among them, the M x is the preset rotation matrix, and g is the first orientation rotation matrix.

[0088] In this way, the first orientation rotation matrix corresponding to each Kikuchi pole combination can be calculated.

[0089] In some examples, the preset rotation matrix M provided in this application x It can be the following formula (3) or other formulas. In short, different EBSD equipment can provide different preset rotation matrices M x .

[0090]

[0091] Substituting formula (3) into the formula g = M x ·M y The first orientation rotation matrix obtained is as follows:

[0092]

[0093] S200, converting the first orientation rotation matrix to obtain a second orientation rotation matrix, and obtaining corresponding orientation difference values ​​according to the first orientation rotation matrix and the second orientation rotation matrix, wherein the second orientation rotation matrix is ​​different from the first orientation rotation matrix.

[0094] In some examples, after obtaining the first orientation rotation matrix corresponding to the Kikuchi pole combination through the above process, the first orientation rotation matrix can be converted and calculated, that is, the first orientation rotation matrix is ​​converted into a second orientation rotation matrix, and the second orientation rotation matrix is ​​different from the first orientation rotation matrix. Then, the orientation difference value is calculated based on the first orientation rotation matrix and the second orientation rotation matrix.

[0095] In some embodiments, converting the first orientation rotation matrix to obtain a second orientation rotation matrix includes:

[0096] S210, converting the first orientation rotation matrix according to a preset conversion method to obtain a corresponding target matrix, wherein the number of elements included in the target matrix is ​​less than the number of elements included in the first orientation rotation matrix;

[0097] S220, converting the target matrix according to the preset conversion method to obtain the second orientation rotation matrix; the second orientation rotation matrix has the same number of rows and columns as the first orientation rotation matrix.

[0098] In some examples, the present application converts a first orientation rotation matrix including a first number of elements into a target matrix with a second number of elements according to a preset conversion method, and the first number of elements is greater than the second number of elements. For example, the first number of elements (also referred to as the product of the number of horizontal and the number of columns) included in the first orientation rotation matrix is ​​3*3, then the second number of elements of the target matrix obtained by converting the first orientation rotation matrix according to the preset conversion method is less than 3*3, and the second number of elements of the target matrix can be 1*3 or 1*4. Then, according to the preset conversion method, the target matrix including the second number of elements is converted into a second orientation rotation matrix with a first number of elements. Since the first number of elements included in the first orientation rotation matrix is ​​different from the second number of elements included in the target matrix, the elements of the second orientation rotation matrix obtained after the first orientation rotation matrix is ​​converted twice based on the preset conversion method are not completely the same as the elements of the first orientation rotation matrix, that is, some elements of the second orientation rotation matrix may be the same as some elements of the first orientation rotation matrix, and another part of the elements of the second orientation rotation matrix are different from another part of the elements of the first orientation rotation matrix, but the first orientation rotation matrix and the second orientation rotation matrix have the same number of rows and columns.

[0099] In some embodiments, the preset conversion method includes any one of the mutual conversion between Miller index and rotation matrix, the mutual conversion between Euler angle and rotation matrix, the mutual conversion between angle axis pair and rotation matrix, and the mutual conversion between four elements and rotation matrix.

[0100] In some examples, crystal orientation can be expressed in multiple ways, such as Miller index, matrix, Euler angle, angular axis pair, and four-element representation. Various orientation representations can be converted to each other. EBSD equipment usually gives the orientation results of the sample to be tested in Euler angles, and other representations can be converted.

[0101] Miller Indices are used to describe the orientation of a crystal plane in a crystal, and are expressed as (h, k, l), where h, k, and l are integers corresponding to the reciprocals of the intercepts of the crystal plane on the three coordinate axes.

[0102] Euler angles describe the rotation of an object around three axes of a coordinate system (usually x, y, and z) through three angles. The form of Euler angles is usually a three-dimensional vector, whose values ​​represent the rotation angles of the object around these three axes, recorded as roll, pitch, and yaw, and are expressed as

[0103] The angular axis pair describes the orientation of the crystal by a rotation angle θ and a rotation axis [r1, r2, r3]. The rotation axis is a unit vector that indicates the direction of rotation, while θ indicates the angle of rotation.

[0104] Quaternion is a mathematical tool for representing rotation in three-dimensional space. Quaternion geometrically uses the rotation axis and the angle of rotation around the axis to represent angular displacement. Compared with the rotation matrix, quaternion only needs four elements to represent the rotation, while the rotation matrix needs nine elements. Quaternion can be represented as a four-dimensional vector q = (w, x, y, z), where w is the real part and x, y, z are the imaginary parts.

[0105] Taking the conversion between the first orientation rotation matrix g and the Euler angle form as an example, the first orientation rotation matrix g can represent the orientation of an object in three-dimensional space through a series of rotation operations (such as rotation around the X-axis, Y-axis, and Z-axis). Euler angles describe the order and size of these rotation operations through three angles (usually called yaw angle, pitch angle, and roll angle). Therefore, converting the first orientation rotation matrix g to Euler angles is to find these three angles so that their combination can produce the same effect as the first orientation rotation matrix g. Conversely, converting the Euler angles back to a rotation matrix is ​​to reconstruct a new rotation matrix based on these three angles. This new rotation matrix is ​​the second orientation rotation matrix g'. In an orthogonal coordinate system, the first orientation matrix g and Euler angles There is a conversion relationship as shown in formula (5):

[0106]

[0107] Since the first orientation rotation matrix g calculated by directly substituting the Kikuchi polar coordinates and the corresponding crystal direction index is not a strictly orthogonal matrix, and the sum of the squares of the row (column) components is not strictly equal to 1. In addition, different expressions of crystal orientation (including rotation matrix, Miller index, Euler angle, angle axis pair and four elements, etc.) can be converted to each other. First, the first orientation rotation matrix g is converted into Euler angle, and then the Euler angle is converted into matrix form to obtain the second orientation rotation matrix g' as follows (6):

[0108]

[0109] In some embodiments, the formula for calculating the orientation difference value includes:

[0110] C=|u-u'|+|v-v'|+|w-w'|+|r-r'|+|s-s'|+|t-t'|+|h-h'|+|k-k'|+|l-l'|(7)

[0111] Wherein, C is the orientation difference value,

[0112] →

[0113] is the first orientation rotation matrix, is the second orientation rotation matrix.

[0114] The second orientation rotation matrix g' is a strictly orthogonal matrix that satisfies the constraints of the orthogonal matrix, while the first orientation rotation g is not a strictly orthogonal matrix. Therefore, the first orientation rotation matrix g and the second orientation rotation matrix g' are not completely equal. The absolute values ​​of the differences between the components of the first orientation rotation matrix g and the second orientation rotation matrix g' are added together to obtain the orientation difference value of the Kikuchi pole combination.

[0115] S300, screening a target Kikuchi pole combination according to the orientation difference values ​​corresponding to all the Kikuchi pole combinations.

[0116] In some examples, the EBSD equipment usually gives the crystal orientation data of the sample to be tested in Euler angles, and other expressions can be converted. Every three non-collinear Kikuchi poles in a diffraction pattern can form a "Kikuchi pole combination", corresponding to a crystal orientation (which can be the first orientation rotation matrix g, or the Euler angle corresponding to the first orientation rotation matrix g) and an orientation difference value C. In general, the larger the orientation difference value C, the lower the calculation accuracy of the crystal orientation of the sample to be tested.

[0117] In some embodiments, the step S300 of screening the target juchi pole combination according to the orientation difference values ​​corresponding to all the juchi pole combinations comprises:

[0118] S310, obtaining a target threshold value according to the orientation difference values ​​corresponding to all the kikuchi pole combinations;

[0119] S320, screening out the target Juchi pole combination that reaches the target threshold from all the Juchi pole combinations.

[0120] In some examples, the present application can screen out an appropriate orientation difference value from the orientation difference values ​​corresponding to all the Juchi pole combinations as the target threshold, and then compare the orientation difference values ​​corresponding to all the Juchi pole combinations with the target threshold, and screen out the Juchi pole combination corresponding to the orientation difference value greater than (or greater than or equal to) the target threshold as the target Juchi pole combination.

[0121] In some embodiments, the step S310 of obtaining a target threshold value according to the orientation difference values ​​corresponding to all the chrysanthemum pole combinations comprises:

[0122] S311, selecting n orientation difference values ​​from all the orientation difference values ​​according to their numerical values; the maximum value of the n orientation difference values ​​is smaller than any remaining orientation difference value, and n≥2 is a positive integer;

[0123] S312: Determine the maximum value of the n orientation difference values ​​as the target threshold.

[0124] In some examples, the orientation difference values ​​corresponding to all the Kikuchi pole combinations are arranged in ascending order, and the first n orientation difference values ​​can be selected from the arranged multiple orientation difference values ​​according to the situation, and the nth orientation difference value (i.e., the maximum value among the n orientation difference values) among the first n orientation difference values ​​arranged in ascending order is set as the target threshold.

[0125] Of course, the orientation difference values ​​corresponding to all the Kikuchi pole combinations can also be arranged in order from large to small, and the last n orientation difference values ​​can be selected from the arranged multiple orientation difference values ​​according to the situation, and the nth orientation difference value (that is, the maximum value among the n orientation difference values) among the last n orientation difference values ​​arranged from large to small can be set as the target threshold.

[0126] The present application performs orientation calculations on all "Kikuchi pole combinations" to obtain the corresponding first orientation rotation matrix and difference value calculations to obtain the corresponding orientation difference values. The larger the orientation difference value, the lower the accuracy of the orientation result (i.e., the first orientation rotation matrix or the Euler angle corresponding to the first orientation rotation matrix). The present application can evaluate the accuracy of the orientation results calculated by each Kikuchi pole when the theoretical orientation value is unknown by comparing the orientation difference values. The present application can screen all Kikuchi pole combinations appearing in a diffraction pattern by screening the orientation difference values, and can exclude almost all unreliable Kikuchi pole combinations, completely avoiding the orientation calculation results with large errors, and greatly improving the orientation calculation accuracy.

[0127] For example,

[0128] 6) All the "three-Kikuchi-pole combinations" are sorted from small to large according to the orientation difference value. The target threshold can be set according to the situation. The Kikuchi-pole combinations that are not greater than the threshold are selected, and their orientation calculation results are considered reliable. We selected the top five Kikuchi-pole combinations with orientation difference values, and they can all obtain high-precision orientation results. After verification, the orientation calculation errors of these selected Kikuchi-pole combinations are all less than 1°, and most of them are within 0.5°.

[0129] Effect of the invention:

[0130] The present application can evaluate the accuracy of orientation calculation results when the theoretical orientation value is unknown, and can screen out reliable Kikuchi pole combinations for orientation calculation, completely avoiding the occurrence of orientation results with large errors, and greatly improving the orientation calculation accuracy.

[0131] like Figure 2 As shown in the figure, taking cubic stainless steel as the research object to obtain the electron backscatter diffraction pattern as an example, the second coordinate of the center of the electron backscatter diffraction pattern and the distance value DD between the sample to be tested and the screen are obtained from the EBSD equipment. It is assumed that the second coordinate of the center of the electron backscatter diffraction pattern is (676, 550) and DD is 668 (number of pixels).

[0132] Next, the Kikuchi bands in the diffraction pattern are identified, the first coordinates of the Kikuchi pole are obtained, and the crystal orientation index corresponding to the Kikuchi pole is calibrated. After that, every three non-collinear Kikuchi poles are taken as a combination, and all "Kikuchi pole combinations" are established for orientation calculation.

[0133] For example, for the Kikuchi pole combination AFH and the Kikuchi pole combination BDH, the first coordinates and crystal direction indexes of the Kikuchi poles A, F, H and B, D, H are respectively substituted into the formula (1) in the above embodiment to calculate the corresponding target matrix M y Considering the coordinate transformation, add the preset rotation matrix M shown in formula (3) in the above embodiment x , and finally get the orientation result, that is, the first orientation rotation matrix g = M x ·M y The orientation matrices of the AFH and BDH combinations thus obtained are respectively the following formulas (8) and (9):

[0134]

[0135] Then, according to formula (5), the first orientation rotation matrix g is AFH and the first orientation matrix g BDH Converted into Euler angle form, the first orientation rotation matrix g AFH The Euler angles are (18.93, 37.78, 42.66), and the first orientation matrix g BDHThe Euler angles are (17.87, 37.78, 48.21).

[0136] Then, according to formula (5), the first orientation rotation matrix g is AFH The Euler angles are converted into matrix form to obtain the corresponding second orientation rotation matrix g' AFH , the first orientation rotation matrix g BDH The Euler angles are converted into matrix form to obtain the corresponding second orientation rotation matrix g' BDH , where the second orientation rotation matrix g' AFH and the second orientation rotation matrix g' BDH They are the following formulas (10) and (11) respectively:

[0137]

[0138] The second orientation rotation matrix g' is obtained AFH and the second orientation rotation matrix g' BDH Substitute into the formula (6) in the above embodiment to calculate the orientation difference value, wherein the orientation difference values ​​corresponding to the Kikuchi pole combination AFH and the Kikuchi pole combination BDH are respectively calculated as: C AFH =0.0400, C BDF =0.2440.

[0139] Taking the orientation results (19.5, 37.9, 42.3) provided by the EBSD equipment as the theoretical values, the orientation results of the Kikuchi pole combination AFH, that is, the Euler angles corresponding to the first orientation rotation matrix (18.93, 37.78, 42.66), and the orientation results of the Kikuchi pole combination BDH, that is, the Euler angles corresponding to the first orientation rotation matrix (17.87, 37.78, 48.21), respectively, can be calculated to obtain the orientation difference angle between the orientation results of the Kikuchi pole combination AFH and the theoretical values. The orientation difference angles between the orientation results of the Kikuchi pole combination BDH and the theoretical values ​​are: the orientation difference angle of the Kikuchi pole combination AFH is 0.38°, and the orientation difference angle of the Kikuchi pole combination BDH is 4.73°. This result shows that the orientation calculation results of the Kikuchi pole combination AFH are more accurate and have a smaller deviation from the theoretical value.

[0140] Further verify the relationship between the orientation difference value and the orientation difference angle. Orientation calculation and orientation difference value calculation are performed for all Kikuchi pole combinations in the diffraction pattern. The orientation results (19.5, 37.9, 42.3) provided by the EBSD equipment are used as theoretical values ​​to calculate the orientation difference angle between the orientation results and theoretical values ​​of all Kikuchi pole combinations. Analyze the relationship between the orientation difference angle and the orientation difference value, and the results are as follows Figure 4 shown. Figure 4Each point in represents a Kikuchi pole combination, the horizontal axis is the orientation difference angle of the Kikuchi pole group, and the vertical axis is the orientation difference value of the Kikuchi pole group. It can be seen that the orientation difference value and the orientation difference angle are positively correlated as a whole. It can be considered that the smaller the orientation difference value, the higher the accuracy of the orientation result. Therefore, the orientation calculation results can be evaluated according to the orientation difference value.

[0141] All the Kikuchi pole combinations are sorted from small to large according to the orientation difference value. The first five Kikuchi pole combinations with the smallest orientation difference value are selected, and the target threshold is set to 0.025. The selected Kikuchi pole combinations are: BFH, BHI, BGH, CHI, EGH. The orientation results calculated by them are BFH (18.77, 35.17, 42.90), BHI (18.82, 35.17, 42.62), BGH (18.73, 35.17, 43.17), CHI (18.85, 35.17, 42.61), EGH (18.82, 37.78, 43.03).

[0142] Taking the orientation values ​​(19.5, 37.9, 42.3) provided by the EBSD equipment as theoretical values, the orientation difference angles of these Kikuchi pole combinations are calculated, and the calculation results are: BFH (0.46°), BHI (0.49°), BGH (0.55°), CHI (0.46°), EGH (0.47°). It can be seen that the orientation results of the screened Kikuchi pole combinations are all of high accuracy, and it can be considered that these Kikuchi pole combinations are reliable.

[0143] According to the above embodiments, the present application only needs to calculate the orientation difference value corresponding to each Kikuchi pole combination to evaluate the orientation calculation accuracy and screen the Kikuchi pole combination. There is no need to know the theoretical value of the orientation. Calculating the orientation difference angle according to the theoretical value of the orientation is only to verify the relationship between the orientation difference value and the orientation difference angle. In general, the orientation difference value and the orientation difference angle are positively correlated. The larger the orientation difference value, the larger the orientation difference angle, and the lower the accuracy of the orientation result. Selecting the first five groups of Kikuchi poles with smaller orientation difference values ​​can obtain high-precision orientation results, and almost all unreliable Kikuchi pole combinations can be excluded, completely avoiding the occurrence of orientation results with large errors, thereby greatly improving the accuracy of the orientation calculation.

[0144] Furthermore, the present application also provides a computer storage medium having a computer program stored thereon, and when the program is executed by a processor, the Kikuchi polar screening method based on electron backscatter diffraction pattern in the above-mentioned embodiment is implemented.

[0145] The above specific implementations further describe the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above is only a specific implementation of the present application and is not limited to the protection scope of the present application. Without departing from the purpose of the basic characteristics of the present application, the present application can be embodied in various forms. Therefore, the implementation forms in the present application are used for explanation rather than limitation. Since the scope of the present application is limited by the claims rather than the specification, and all changes within the scope defined by the claims or within the equivalent scope of the scope defined by the claims should be understood to be included in the claims. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A Kikuchi polar screening method based on electron backscatter diffraction pattern, characterized in that: include: According to the first coordinate and crystal direction index of each kikuchi pole in the electron backscatter diffraction pattern of the sample to be tested, as well as the second coordinate of the center of the electron backscatter diffraction pattern and the distance value between the sample to be tested and the screen of the probe, the first orientation rotation matrix corresponding to each kikuchi pole combination included in the electron backscatter diffraction pattern is calculated; the second coordinate and the first coordinate are coordinates in the same coordinate system, and the kikuchi pole combination includes three kikuchi poles that are not collinear; Converting the first orientation rotation matrix to obtain a second orientation rotation matrix, and obtaining corresponding orientation difference values ​​according to the first orientation rotation matrix and the second orientation rotation matrix, wherein the second orientation rotation matrix is ​​different from the first orientation rotation matrix; The target Kikuchi pole combination is screened according to the orientation difference values ​​corresponding to all the Kikuchi pole combinations.

2. The method for screening Kikuchi poles based on electron backscatter diffraction patterns according to claim 1, characterized in that: Obtaining the first coordinate and crystal direction index of the kikuchi pole includes: According to the electron backscatter diffraction pattern, all the kikuchi poles are identified and numbered respectively; The first coordinate of the Kikuchi pole in a preset coordinate system is obtained, and the crystal direction index of the Kikuchi pole in the crystal coordinate system corresponding to the sample to be tested is obtained. The preset coordinate system is established with any point in the plane where the electron backscatter diffraction pattern is located as the origin.

3. The method for screening Kikuchi poles based on electron backscatter diffraction patterns according to claim 1, characterized in that: According to the first coordinates and crystal direction index of each kikuchi pole in the electron backscatter diffraction pattern of the sample to be tested, the second coordinates of the center of the electron backscatter diffraction pattern, and the distance between the sample to be tested and the screen of the probe, the first orientation rotation matrix corresponding to each kikuchi pole combination included in the electron backscatter diffraction pattern is calculated; The second coordinate and the first coordinate are coordinates in the same coordinate system, and the kikuchi pole combination includes three kikuchi poles that are not collinear, including: Calculate the target matrix corresponding to each of the Juchi pole combinations according to the distance value, the second coordinate, and the first coordinate and the crystal direction index corresponding to each of the Juchi poles in all the Juchi pole combinations; According to the preset rotation matrix and the target matrices corresponding to all the Kikuchi pole combinations, the first orientation rotation matrices corresponding to each Kikuchi pole combination are calculated respectively.

4. The method for screening Kikuchi poles based on electron backscatter diffraction patterns according to claim 3, characterized in that: The formula for calculating the target matrix includes: Wherein, (x, y) is the first coordinate of the kikuchi pole, (x0, y0) is the second coordinate, [hkl] is the crystal direction index of the kikuchi pole, DD is the distance value, M y is the target matrix; The formula for calculating the first orientation rotation matrix includes: g=M x ·M y Among them, the M x is the preset rotation matrix, and g is the first orientation rotation matrix.

5. The method for screening Kikuchi poles based on electron backscatter diffraction patterns according to claim 1, characterized in that: The converting according to the first orientation rotation matrix to obtain the second orientation rotation matrix comprises: The first orientation rotation matrix is ​​transformed according to a preset transformation mode to obtain a corresponding target matrix, wherein the number of elements included in the target matrix is ​​less than the number of elements included in the first orientation rotation matrix; The target matrix is ​​transformed according to the preset transformation method to obtain the second orientation rotation matrix; the second orientation rotation matrix has the same number of rows and columns as the first orientation rotation matrix.

6. The method for screening Kikuchi poles based on electron backscatter diffraction patterns according to claim 5, characterized in that: The preset conversion method includes any one of the mutual conversion between Miller index and rotation matrix, the mutual conversion between Euler angle and rotation matrix, the mutual conversion between angle axis pair and rotation matrix, and the mutual conversion between four elements and rotation matrix.

7. The method for screening Kikuchi poles based on electron backscatter diffraction patterns according to claim 1, characterized in that: The formula for calculating the orientation difference value includes: C=|u-u'|+|v-v'|+|w-w'|+|r-r'|+|s-s'|+|t-t'|+|h-h'|+|k-k'|+|ll' Wherein, C is the orientation difference value, → is the first orientation rotation matrix, is the second orientation rotation matrix.

8. The method for screening Kikuchi poles based on electron backscatter diffraction patterns according to claim 1, characterized in that: The step of screening the target juchi pole combination according to the orientation difference values ​​corresponding to all the juchi pole combinations comprises: Obtaining a target threshold value according to the orientation difference values ​​corresponding to all the kikuchi pole combinations; The target Kikuchi pole combination that reaches the target threshold is screened out from all the Kikuchi pole combinations.

9. The method for screening Kikuchi poles based on electron backscatter diffraction patterns according to claim 8, characterized in that: The target threshold value is obtained according to the orientation difference values ​​corresponding to all the kikuchi pole combinations, including: n orientation difference values ​​are selected from all the orientation difference values ​​according to their numerical values; the maximum value of the n orientation difference values ​​is less than any remaining orientation difference value, and n≥2 is a positive integer; The maximum value of the n orientation difference values ​​is determined as the target threshold.

10. A computer storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the Kikuchi polar screening method based on electron backscatter diffraction pattern as described in any one of claims 1 to 9 is implemented.

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